Turbomachines, e.g., compressors, typically include one or more seals arranged therein to substantially segregate a high pressure fluid from a low pressure fluid and/or the atmosphere. For example, a high pressure centrifugal compressor may include a compressor bundle installed in the casing bore of a compressor casing and/or housing with an inlet side (low-pressure) and a working chamber (high-pressure). One or more seals, e.g., O-rings, may be mounted about the compressor bundle and configured to seat against the inner surface of the compressor casing upon insertion of the compressor bundle in the casing bore.
In a compressor with operating pressures greater than 10,000 psi, typical compressor bundles inserted therein may utilize O-rings as well as back-up ring seals. At high pressures in compressors, however, it has been discovered that the O-rings utilized therein show increased failure rates for at least two reasons. First, under high pressure, the casing itself expands or grows radially, increasing the gap between the compressor bundle and the inner surface of the casing. The increased size of the gap may promote extrusion of the O-ring into the gap, thereby increasing failure rates. Second, O-rings may absorb fluids, e.g., carbon dioxide, at high pressure and then blister and/or explode when the high pressure is reduced and/or released.
What is needed, then, is an alternative to traditional O-rings providing sealing performance at high pressure, e.g., greater than 10,000 psi.